DESCRIPTION: In the PI's working model of visual information processing, three segregated parallel pathways (magnocellular (M), parvicellular (P), and koniocellular (K)) from the lateral geniculate nucleus (LGN) to primary visual cortex (V1) are utilized by the laminar and compartmental (i.e. cytochrome oxidase (CO) blob and interblob) circuitry of V1 to synthesize new output pathways appropriate for the next steps of analysis. Within this scheme, separate output layers and compartments of V1 have distinct modes for integrating signals from all three input pathways and generating output signals that support extrastriate areas, specialized not for specific attributes, but for more complex visual analysis. In light of this model, the project's broad aims are to test the significance of these pathways, define how input pathways engage the circuitry of V1 layers and compartments, and discern the strategies utilized by the output pathways to support V1 target areas. This proposal focuses on the K and the M input pathways and on output pathways to visual area 2 (V2), the dorsal medial visual area (DM), and the middle temporal visual area (MT). The specific aims are designed to test hypotheses generated by our working model. In Aim I, the PI will examine the K pathway and how this and other pathways are integrated within the CO-blobs of V1. In Aim II, she will determine the relationship of LGN K (or M) cell activity to eye movements or to behavioral relevance. In Aim III she will define the organization of V1 output pathways from CO-blob columns. The results of this proposed studies will contribute important new information to the fundamental understanding of how the brain processes visual information and of brain architecture in general.